The spinal cord is a complex cable of nerves that connects the brain to most of the rest of the body. It is made up of bundles of long nerve fibers and has two basic functions: to permit some reflex movements and to carry messages to and from the brain.
The spinal cord and reflex action.
Simple reflexes are controlled by the spinal cord. The message travels from the sense receptors near the skin through the afferent nerve fibers to the spinal cord. In the spinal cord, the messages are relayed through association neurons to the efferent nerve fibers, which carry them to the muscle cells that cause the reflex movement.